STRESS-STRAIN RIPSTOP CURVES
1. Motivation and testing device
The stress-strain test is a classic in the science of strength of
materials, because it allows accurately knowledge of its elastic
Why not apply it to the tissue of paragliding?
This is precisely what we have done in the laboratory. This trial,
together with the porosity, allowed us to validate the tissue used in
the Ascender. In general, this test should be done on any
unknown fabric, or with little data from the manufacturer, or to control its
Can not be done on paragliders in use, because it is a destructive test and requires a portion of tissue.
Fig 1. Testing device
The test system consists of loading progressively a ripstop tissue strip of 5 cm
wide, and simultaneously measuring the distance between two reference
points marked on the tissue, and the applied load. The trial continues gradually until rupture of the material, or to the
point where you want to start the unloading and check for the permanent
The result is a table with the pair of values (distance (mm), load (kg)). For a stress-strain curve normalized, these values are converted as follows:
Stress (kg/cm) = Load (kg) / 5 cm
Strain = ( (Distance / Initial distance) ) -1 )
Note: The data presented here are not official, and do not represent
the average characteristics of the tissues.
The results have only theoretical interest
The manufacturer should be
consulted for precise details of each of the different grades manufactured